The chloroaluminate ion storage properties of various carbonaceous electrodes, namely soft carbon (SC), hard carbon (HC), activated carbon (AC), and ordered mesoporous carbon CMK-8, are investigated. The effects of carbon crystallinity, surface area, and pore size are systematically examined. Due to their non-ideal graphitic structures, the charge–discharge capacities of SC and HC electrodes are unfavorable for practical applications, although SC, with its relatively high crystallinity, outperforms HC. The high-surface-area AC and CMK-8 exhibit reversible capacities of 59.0 and 100.5 mAh g−1, respectively, at 300 mA g−1. Pore size and geometry play important roles in determining the electrochemical properties. The CMK-8 framework not only serves as an electronic conduction pathway but also provides interpenetrating three-dimensional open channels for electrolyte accessibility and complex AlCl4− anion transport. The charge storage mechanism of the CMK-8 electrode, confirmed by electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry, has a capacitive contribution and a diffusion-controlled intercalation/deintercalation contribution. Based on this unique mechanism, great rate capability, and excellent cyclability of the CMK-8 electrode are demonstrated.
- Interpenetrating open channels
- Ionic liquid electrolyte
- Pore size effects
- Porous carbon electrodes